US20080218664A1 - Fluorescent lamp and imaging device usign the same - Google Patents

Fluorescent lamp and imaging device usign the same Download PDF

Info

Publication number
US20080218664A1
US20080218664A1 US12/033,907 US3390708A US2008218664A1 US 20080218664 A1 US20080218664 A1 US 20080218664A1 US 3390708 A US3390708 A US 3390708A US 2008218664 A1 US2008218664 A1 US 2008218664A1
Authority
US
United States
Prior art keywords
phosphor
fluorescent lamp
layer
phosphors
light
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US12/033,907
Other languages
English (en)
Inventor
Shin Imamura
Kenji Okishiro
Masaki Nishikawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Display Devices Ltd
Japan Display Inc
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Assigned to HITACHI DISPLAY DEVICES, LTD., HITACHI DISPLAYS, LTD. reassignment HITACHI DISPLAY DEVICES, LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: NISHIKAWA, MASAKI, IMAMURA, SHIN, OKISHIRO, KENJI
Publication of US20080218664A1 publication Critical patent/US20080218664A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/38—Devices for influencing the colour or wavelength of the light
    • H01J61/42—Devices for influencing the colour or wavelength of the light by transforming the wavelength of the light by luminescence
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133604—Direct backlight with lamps

Definitions

  • the present invention relates to a phosphor layer with high resolution, long life, high brightness, and good color reproducibility, which is suitable for image display.
  • the present invention also relates to an imaging device using the same, such as a liquid crystal display.
  • An imaging device in the present invention means a device in which a phosphor is excited by being given energy to emit a light, resulting in displaying image information.
  • imaging devices include a non-self-luminous imaging device which is provided with a light source as a back light or side light, in a non-self-luminous display portion, such as a liquid crystal display panel.
  • the above examples also include a whole system for displaying images in which the liquid crystal display panel and the light source mentioned above, are implemented as a display unit, and a driving unit and an image processing circuit or the like are additionally incorporated so as to display images.
  • a liquid crystal display device will be mainly explained hereinafter.
  • color display is performed in a way in which a light emitted from a light source 5 is guided to the side of a liquid crystal display panel by a back light unit, then the light is adjusted in its transmission quantity for each pixel, and one of red color, green color, or blue color is transmitted through after the light is separated, for each pixel in a liquid crystal display panel 2 .
  • a cold cathode fluorescent lamp (CCFL) is used for a light source of a liquid crystal display device.
  • FIG. 5 shows a cross sectional view along the major axis of a CCFL.
  • the CCFL has a structure in which a phosphor 12 is coated on the inner wall of a glass tube 11 and electrodes 13 is provided on the either side of the glass tube.
  • mercury Hg and rare gas (argon Ar or neon Ne) are enclosed as discharge mediums 14 in the tube.
  • a CCFL used for a back light (the same meaning as a light source) of this type has a very long, narrow and characteristic shape, unlike a fluorescent lamp for interior illumination.
  • a fluorescent lamp for interior illumination has a diameter of tube (inner diameter of tube) of about 30 mm and a length of tube of about 1100 mm.
  • a CCFL has, for example, in the case of a 32-inch liquid crystal display device, a diameter of tube (inner diameter of tube) of about 4 mm and a length of tube of about 720 mm.
  • a CCFL is characterized in that its diameter of tube is very small.
  • Such a CCFL is lighted by applying a high voltage between the electrodes 13 of both ends. Electrons emitted from the electrode by applying a voltage, excite mercury Hg, resulting in radiation of an ultraviolet light when the excited mercury Hg returns to a ground state. A phosphor is excited by the ultraviolet light to emit a visible ray to the outside of a tube.
  • a phosphor 12 provided in a CCFL is made by mixing three powders to the extent in which the mixture has a predetermined white chromaticity, the three powders are: a blue phosphor of which luminescent color is blue (main luminescence peak wavelength falls in a range of about 400 nm to about 500 nm); a green phosphor of which luminescent color is green (main luminescence peak wavelength falls in a range of about 500 nm to about 600 nm); and, a red phosphor of which luminescent color is red (main luminescence peak wavelength falls in a range of about 600 nm to about 650 nm).
  • blue phosphor BaMgAl 10 O 17 :Eu 2+ green phosphor LaPO 4 : Tb 3+ , Ce 3+ , and red phosphor Y 2 O 3 :Eu 3+ are generally used.
  • (Ba, Ca, Mg, Sr) 10 (PO 4 ) 6 Cl 2 :Eu 2+ (generally referred to as an SCA phosphor) is sometimes used as a blue phosphor; BaMgAl 10 O 17 :Eu 2+ , Mn 2+ is as a green phosphor; and YVO 4 :Eu 3+ is as a red phosphor.
  • the front part before “:” shows a host material composition
  • the rear part thereafter shows a luminescence center, meaning that part of atoms of the host material is substituted in the luminescence center.
  • LaPO 4 is a host material and part of lanthanum La is substituted by terbium Tb which is a luminescence center.
  • Cerium Ce is added thereto as a sensitizer which sensitizes luminescence of Tb.
  • LaPO 4 :Tb 3+ , Ce 3+ may be described as (La, Tb, Ce)PO 4 as well.
  • the visible ray emitted from the CCFL enters a liquid crystal display panel 2 opposed to the back light unit 1 , after transmitting through optical members disposed directly above the CCFL, the optical members including a diffuser plate 6 , a prism sheet 7 , and a reflective polarizer 8 or the like.
  • a reflector 4 is disposed directly under the CCFL, and the light reflected by the reflector also enters the liquid crystal display panel 2 , after transmitting through the aforementioned optical members.
  • the liquid crystal display panel 2 has a cross-sectional structure shown in FIG. 9 . That is, the structure includes: a pair of glass substrates 21 ( 21 A, 21 B) which are opposed to each other; two alignment layers 23 coated respectively on the inner surfaces of the glass substrates; and liquid crystal 24 and color filters 25 (red color 25 A, green color 25 B, blue color 25 C) which are both sandwiched between the glass substrates.
  • a distance between the glass substrates 21 ( 21 A- 21 B) is maintained by a spacer 26 .
  • Polarizers 22 ( 22 A, 22 B) are disposed on the outside of the pair of substrates 21 ( 21 A, 21 B), respectively.
  • Liquid crystal 24 is uniformly oriented by the alignment layer 23 , and driven by applying a voltage to a group of electrodes formed for each pixel (not shown in FIG. 9 ). When applying a voltage, liquid crystal rotates according to an electric field occurred by the voltage, which alters a refractive index of the liquid crystal layer, resulting in adjustment of a transmission quantity of light.
  • Color filters 25 separate the white light W emitted from the back light unit 1 , into red light R, green light G, and blue light B, for each pixel, and transmits one of the three lights.
  • a liquid crystal display device performs color display in this way where a light emitted from a light source provided in a back light unit is adjusted in transmission quantity thereof by a liquid crystal display panel, for each pixel, and separates the light with a color filter which transmits one of lights of red, green and blue, for each pixel.
  • JP-A No. 2002-56815 can be cited. However, according to the embodiments disclosed in the literature, brightness of a fluorescent lamp has not been sufficiently enhanced.
  • liquid crystal display devices have been widely used mainly in the market of large-sized liquid crystal TV receivers, and lower cost and higher image quality have been demanded.
  • higher brightness and reduction in variation in chromaticity of a CCFL, a light source should be achieved.
  • a CCFL with higher brightness can omit some of the optical members (for example, luminance improving film etc.) that intervene between the CCFL and a liquid crystal display panel, which enables a liquid crystal display device to be produced at a lower cost.
  • chromaticity of a CCFL is a factor which greatly affects the image quality of a liquid crystal display device, therefore reduction of the variation is an important issue.
  • a human being looks directly at a light source through a liquid crystal display panel, because the display device adjusts the transmission quantity of a light emitted from a light source with the liquid crystal display panel, and displays images by separating the light. Therefore, the chromaticity property of a CCFL directly affects the color tone of a liquid crystal display device.
  • the present invention will solve these issues that luminance of a light source represented by a CCFL should be enhanced and variation in chromaticity should be reduced, with a means described below, in order to enable a liquid crystal display device which is growing larger and larger to be produced at a lower cost, and to be capable of offering higher image quality, at a same time.
  • the present invention is intended to solve the issues that luminance of a light source should be enhanced and variation in chromaticity should be reduced, and to provide an imaging device with higher brightness and capability of offering higher image quality, with the use of the following means.
  • the above purpose can be achieved by a fluorescent lamp and an imaging device using the same, in which the fluorescent lamp is produced in the following way: in a fluorescent lamp having a structure in which a phosphor layer made by laminating phosphor particles is provided, and a primary light is generated by discharge to excite the phosphor layer, resulting in generating a secondary light; the phosphor layer is composed of at least two types of phosphors, and at least the most outer surface layer on the side of emitting the secondary light, along the thickness direction of the phosphor layer, is a phosphor layer of one of the phosphors (the first phosphor); and the rest portion of the phosphor layers except, is a layer of the mixed phosphors including plural phosphors having respective emitting colors.
  • the above purpose can also be achieved by a fluorescent lamp and an imaging device using the same: in which the fluorescent lamp is produced in the following way: in a fluorescent lamp having a structure in which a phosphor layer made by laminating phosphor particles is provided, the phosphor layer being invented in the present invention, and a primary light is generated by discharge to excite the phosphor layer, resulting in generating a secondary light; the phosphor layer is composed of at least two types of phosphors, and when assuming a weight ratio of one of a phosphor (the first phosphor) to the entire phosphors of the entire layer is x, and another weight ratio of the first phosphor to the phosphors included in the most outer surface layer on the side of emitting the secondary light, is y, y falls in the range of 0 ⁇ x ⁇ y ⁇ 1.
  • the present invention described above can be remarkable in its advantages by setting the phosphor with the first luminescent color to be any one of single color luminescence phosphors of red, green, or blue.
  • the present invention described above can be remarkable in its advantages by setting the median diameter d 50 of the phosphor with the first luminescent color to be 3.0 ⁇ m or less.
  • the present invention described above can be remarkable in its advantages by completely covering the inner surface of the lamp with the phosphor layer, in the above fluorescent lamp.
  • the present invention described above can be remarkable in its advantages by setting the fluorescent lamp to be a white emitting fluorescent lamp with a cold cathode structure having a phosphor layer containing a red emitting phosphor, a green emitting phosphor, and a blue emitting phosphor, in the above fluorescent lamp.
  • the present invention described above can be remarkable in its advantages by setting the median diameter d 50 of the phosphors used in the above fluorescent lamp except the first phosphor, to fall in the range of 1.0 ⁇ m to 10.0 ⁇ m.
  • a phosphor layer structure which has partially a layer of a single color layer can utilize ultraviolet light more efficiently than another layer structure in which the whole phosphor layer is composed of mixed colors of red, blue, and green. Namely, the former can enhance luminance of a fluorescent lamp more greatly than the latter.
  • a fluorescent lamp may be sometimes costly to form a complete single color layer on the inner wall of the lamp, because the shape of a lamp is long and narrow. As a result of examination of how easy a phosphor layer can be formed, an ultraviolet light has been utilized efficiently even in the case where phosphors are mixed.
  • the layer structure can utilize an ultraviolet light efficiently, similarly to the layer structure mentioned above.
  • these advantages become remarkable when particle size and the layer shape of a phosphor satisfy the above specific requirements.
  • a content ratio among the three colors which was simply calculated when forming a layer, generally differs from a luminescence ratio among the three colors.
  • a luminescence ratio of the three colors also differs depending upon layer forming conditions. It is difficult to adjust color because a change of an amount of a color affects other two colors. These factors cause variation in chromaticity of a fluorescent lamp, and the variation cannot be reduced easily in layer structures at present.
  • a layer composed of one single color is an independent layer, therefore the layer structure is less likely to be affected by layer forming conditions, unlike a mixed layer.
  • color can be easily adjusted because the color can be independently altered in its amount of use.
  • a layer structure according to an aspect of the present invention shows less variation in chromaticity of a fluorescent lamp.
  • Advantages of the present invention are effective without being limited to the shape or excitation method of a fluorescent lamp, because it is based on the above principles.
  • the above CCFL lamp is only an example, and advantages of the present invention are also effective in the case of other lamps, for example, a fluorescent lamp with a flat shape, a hot cathode fluorescent lamp (HCFL), or a fluorescent lamp using an ultraviolet light generated by Xe discharge, as an excitation source.
  • HCFL hot cathode fluorescent lamp
  • a fluorescent lamp using an ultraviolet light generated by Xe discharge as an excitation source.
  • advantages of the present invention are effective without being limited to the type of a phosphor.
  • the above phosphor is only an example, and advantages of the present invention are also effective in the case where another type of a phosphor is used.
  • a conventional fluorescent lamp is coated on its inner surface of the tube with fine particles of Y 2 O 3 which do not emit light, as a protective layer of a phosphor.
  • the present invention has an advantage that the fine particles of Y 2 O 3 can be omitted with the use of a single layer of a phosphor.
  • a method for forming a single layer of a phosphor on inner surface of a fluorescent lamp according to an aspect of the present invention can enhance luminance and reduce variation in chromaticity without an additional manufacturing cost in comparison with a conventional fluorescent lamp, when conventionally-used Y 2 O 3 which does not emit light is omitted.
  • enhancement of luminance and reduction of variation in chromaticity in a light source can be satisfied at a same time, with the use of the above means. Furthermore, an imaging device capable of offering high image quality can be obtained by using such a light source.
  • FIG. 1 is a diagram showing a structure of a layer of a phosphor according to an aspect of the present invention
  • FIG. 2 is a graph comparing luminance property of the present invention to that of the conventional phosphor
  • FIG. 3 is a graph showing the property of the relative luminance of the green phosphor
  • FIG. 4 is a diagram showing an exploded perspective view of a liquid crystal display device
  • FIG. 5 is a diagram showing an outline of a cross-sectional structure of a CCFL
  • FIG. 6 is a diagram showing an outline of a cross-sectional structure of a HCFL
  • FIG. 7 is a diagram showing a schematic cross-sectional structure of an EEFL
  • FIG. 8 is a diagram showing a schematic cross-section of a flat light source.
  • FIG. 9 is a diagram showing a schematic cross-sectional structure of a liquid crystal display panel.
  • a liquid crystal display device in the present embodiments is composed of a back light unit 1 and a liquid crystal display panel 2 , as shown in FIG. 4 .
  • the back light unit 1 includes a white light source 5 , a drive circuit 9 (inverter) for lighting the light source, a frame 3 , a reflector 4 , a diffuser plate 6 , a prism sheet 7 , and a reflective polarizer 8 .
  • the above back light unit is an example; therefore, the unit need not include all of the component parts mentioned above, or may add another part.
  • a back light unit means what illuminates the liquid crystal display panel 2 in order to form images.
  • a CCFL shown in FIG. 5 was used as a white light source.
  • a CCFL using a phosphor layer which was mixed with a red phosphor, green phosphor, and blue phosphor was produced as a conventional phosphor.
  • a CCFL was produced in a way in which a phosphor layer of a green phosphor was produced as an independent layer, which was added to a phosphor layer mixed with red, green, and blue phosphors. How to produce a CCFL and an IPS mode liquid crystal display device using the CCFL will be described below.
  • a suspension In order to form a conventional phosphor, a suspension was employed, in which a blue phosphor BaMgAl 10 O 17 :Eu 2+ , green phosphor LaPO 4 :Tb 3+ , Ce 3+ , and red phosphor Y 2 O 3 :Eu 3+ were mixed as a phosphor.
  • a suspension using a green phosphor LaPO 4 :Tb 3+ , Ce 3+ was produced.
  • the median diameters d 50 of particles of these all phosphors were in the range of 1.0 ⁇ m to 10.0 ⁇ m.
  • the median diameters of d 50 were measured by a “Coulter Counter” (Beckman Coulter, Inc.).
  • a layer of phosphor was formed using suspension mixed with three color phosphors.
  • two layers of phosphors were formed: one layer was formed by using a single suspension of green phosphor; and the other layer by using a suspension mixed with three color phosphors.
  • the glass tube is made of Koval glass, and has its diameter of 3 mm.
  • the phosphor was adhered to the inner wall of a glass by baking the glass tube.
  • An electrode was then attached thereto and one side of the glass tube is sealed.
  • Gas pressure in the glass tube was adjusted by pouring rare gas, such as argon Ar and neon Ne, and exhausting the gas, from the opposite side of the sealed side. After pouring mercury additionally, the glass tube was sealed. Finally, aging processing was performed by lighting the glass tube for a certain period of time.
  • CCFLs 5 produced in the above way were disposed on a metal frame 3 .
  • the direct under-light system is employed, in which plural CCFLs are disposed planarly side by side.
  • a reflector 4 which is used for efficiently utilizing the light emitted from the CCFLs 5 toward a metal frame 3 , was disposed between the metal frame 3 and the CCFLs 5 .
  • a diffuser plate 6 was disposed directly above the CCFLs to curb the in-plane distribution of luminance in a liquid crystal display device.
  • a prism sheet 7 and a reflective polarizer 8 were additionally disposed to enhance luminance of a liquid crystal display device.
  • An inverter 9 was connected to the CCFL so that control of lighting of the CCFL was performed by driving of the inverter. These parts are collectively called the back light unit 1 .
  • a liquid crystal display panel 2 was disposed directly above the back light unit 1 , in which the liquid crystal display panel had a color filter which adjusted transmission quantity of light from the back light (white light source CCFL), and which separated the light into red light, green light, and blue light, for each pixel.
  • CCFL white light source
  • FIG. 9 A cross-sectional schematic diagram of the liquid crystal display panel is as shown in FIG. 9 .
  • a 0.5 mm thick glass substrate is typically used for a substrate 21 .
  • an electrode (not shown in FIG. 9 ) was formed for each pixel, and a thin film transistor (TFT), which supplied a voltage to these electrodes, was formed.
  • TFT thin film transistor
  • color filters 25 red 25 A, green 25 B, blue 25 C
  • Alignment layers 23 were formed on the surfaces of the pair of substrates to make the liquid crystal molecule align; further the liquid crystal 24 was sandwiched between the substrates.
  • polarizers 22 22 A, 22 B
  • the combination of the back light unit 1 and the liquid crystal display panel 2 was covered with a frame 10 , resulting in a liquid crystal display device.
  • a layer structure of the present invention which is shown in FIG. 1 , was produced.
  • a layer of the single color phosphor of FIG. 1 is made of a green phosphor.
  • White luminance was measured in the conventional phosphor and the second embodiment, and the result is shown in FIG. 2 , in which values of the second embodiment show relative luminance against values of the conventional phosphor which are 100.
  • a white color temperature in FIG. 2 is 7000K. It can be understood that luminance in the first embodiment is enhanced more than that in the conventional phosphor.
  • the first embodiment had a less variation in chromaticity than the conventional phosphor.
  • This chromaticity value can be obtained by measuring CIE xy coordinates.
  • a phosphor layer which covered a glass tube of the fluorescent lamp without a break had a higher luminance value than a phosphor layer which had a gap, such as a clearance and a hole, occurred due to a break.
  • an ultraviolet light is utilized more efficiently, that is, an amount of ultraviolet light that transmitted through a phosphor layer to the outside of a fluorescent tube can be reduced, by forming a single layer of green color.
  • the second embodiment was produced in the same way as with the first embodiment.
  • a difference between the second embodiment and the first embodiment is that in the second embodiment, two layers of phosphors were formed: one layer was formed by using a single suspension of a blue phosphor BaMgAl 10 O 17 :Eu 2+ ; and the other layer by using a suspension mixed with three color phosphors.
  • Particles of these all phosphors used had diameters of which median diameters d 50 were in the range of 1.0 ⁇ m to 10.0 ⁇ m.
  • a layer structure of the present invention which is shown in FIG. 1 , was produced.
  • a layer of the single color phosphor of FIG. 1 is made of a blue phosphor.
  • White luminance was measured in the conventional phosphor and the second embodiment, and the result is shown in FIG. 2 , in which values of the second embodiment show relative luminance against the values of the conventional phosphor which are 100. It can be understood that luminance in the second embodiment is more enhanced than that in the conventional phosphor. Furthermore, plural samples were produced so that chromaticity values of each liquid crystal display device were measured. As a result of measurements for red, green, blue, and white colors, the second embodiment had a less variation in chromaticity than the conventional phosphor.
  • a phosphor layer which covered a glass tube of the fluorescent lamp without a break had a higher luminance value than a phosphor layer which had a gap, such as a clearance and a hole, occurred due to a break.
  • the third embodiment was produced in the same way as with the first embodiment.
  • a difference between the third embodiment and the first embodiment is that in the third embodiment, two layers of phosphors were formed: one layer was formed by using a single suspension of red phosphor Y 2 O 3 : Eu 3+ ; and the other layer by using a suspension mixed with three color phosphors.
  • a layer of the red single color phosphor was evaluated in the property thereof as median diameters d 50 thereof were varied within the range of 0.05 ⁇ m to 10 ⁇ m, in which the median diameters d 50 were measured by a “Coulter Counter” (Beckman Coulter, Inc.). Particles of all phosphors including red phosphors, which were used for forming the layer of the mixed color phosphors, had a constant and fixed value of median diameters d 50 thereof, the median diameters d 50 being in the range of 1.0 ⁇ m to 10 ⁇ m, in which the median diameters d 50 were measured by a coal tar meter.
  • a layer structure of the present invention which is shown in FIG. 1 , was produced.
  • a layer of the single color phosphor of FIG. 1 is made of a red phosphor.
  • White luminance was measured in the conventional phosphor and the third embodiment, and the result is shown in FIG. 3 , in which values of the third embodiment show relative luminance against the values of the conventional phosphor which are 100.
  • this embodiment using particles of which median diameters d 50 are 3.0 ⁇ m or less, has a higher luminance than the conventional phosphor.
  • the third embodiment had a less variation in chromaticity than the conventional phosphor.
  • a phosphor layer which covered a glass tube of the fluorescent lamp without a break had a higher luminance value than a phosphor layer which had a gap, such as a clearance and a hole, occurred due to a break. From the results, it has been proven that enhancement of luminance and reduction of variation in chromaticity in a CCFL, can be satisfied at a same time with the present invention. Therefore, a liquid crystal display device of high quality can be obtained with the use of such a light source, in which the liquid crystal display device can be produced at a lower cost, while being capable of offering high image quality.
  • This example 4 differs from any one of these examples 1 to 3 in a type of a light source. While CCFLs were used in this embodiments 1 to 3, an HCFL (Hot Cathode Fluorescent Lamp) shown in FIG. 6 was used in this example. Phosphors used for the HCFL were the same as that of these embodiments 1 to 3.
  • the HCFL differs greatly from the CCFL in the fact that a metal electrode portion 13 of the HFCL is a filament electrode.
  • a voltage between two electrodes of the HCFL thermal electrons are emitted from the filament to excite the mercury, resulting in emitting an ultraviolet light therefrom.
  • a phosphor layer which covered a glass tube of the fluorescent lamp without a break had a higher luminance value than a phosphor layer which had a gap, such as a clearance and a hole, occurred due to a break.
  • This example 5 differs from any one of these examples 1 to 3 in a type of a light source. While CCFLs were used in this embodiments 1 to 3, an EEFL (External Electrode Fluorescent Lamp) shown in FIG. 7 was used in this example. Phosphors used for the EEFL were the same as that of these embodiments 1 to 3.
  • the EEFL is produced in a different way from that of the CCFL with regard to forming an electrode portion.
  • a phosphor on a glass tube
  • one side of the glass tube is sealed.
  • mercury which is a discharge medium is introduced within the tube, thereafter the other side of the tube being sealed.
  • a flexible electrode for example, a copper tape, is disposed onto the outside of the glass tube.
  • the glass tube itself serves as a capacitor, thereby a ballast capacitor not being required. Therefore, a multi-lighting system becomes possible in which plural lamps can be lighted with one inverter 9 at a time. This can reduce the number of inverters greatly compared with a CCFL, therefore an EEFL can be produced at a low cost.
  • this example 5 has a higher luminance than the conventional phosphor, in the same way as with this examples 1 to 3. Furthermore, plural samples were produced so that chromaticity values of each liquid crystal display device were measured. As a result of measurements for red, green, blue, and white colors, the fifth embodiment had a less variation in chromaticity than the conventional phosphor.
  • a phosphor layer which covered a glass tube of the fluorescent lamp without a break had a higher luminance value than a phosphor layer which had a gap, such as a clearance and a hole, occurred due to a break.
  • This example 6 differs from any one of these examples 1 to 3 in a type of a light source. While a CCFL was used in these embodiments 1 to 3, a flat light source shown in FIG. 8 was used in this example. Phosphors used for the EEFL were the same as that of these embodiments 1 to 3.
  • a flat light source has a structure composed of a closed box 15 (rear glass 15 A, front glass 15 B) provided with a phosphor 12 , and electrodes 13 ( 13 A, 13 B) disposed on the rear glass, as shown in FIG. 8 .
  • a layer of the single color phosphor was formed on the front glass 15 B.
  • a dielectric body 16 is disposed on the electrodes.
  • a discharge medium 14 is enclosed within the closed box. Examples of light sources include a light source using Xe or mercury, while a discharge medium used varies depending on a type of a flat light source.

Landscapes

  • Vessels And Coating Films For Discharge Lamps (AREA)
  • Liquid Crystal (AREA)
  • Planar Illumination Modules (AREA)
US12/033,907 2007-03-08 2008-02-20 Fluorescent lamp and imaging device usign the same Abandoned US20080218664A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2007-058911 2007-03-08
JP2007058911A JP2008226492A (ja) 2007-03-08 2007-03-08 蛍光ランプ及びそれを用いた画像表示装置

Publications (1)

Publication Number Publication Date
US20080218664A1 true US20080218664A1 (en) 2008-09-11

Family

ID=39741255

Family Applications (1)

Application Number Title Priority Date Filing Date
US12/033,907 Abandoned US20080218664A1 (en) 2007-03-08 2008-02-20 Fluorescent lamp and imaging device usign the same

Country Status (3)

Country Link
US (1) US20080218664A1 (enExample)
JP (1) JP2008226492A (enExample)
CN (1) CN101261920A (enExample)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9494284B2 (en) 2014-03-05 2016-11-15 Sharp Kabushiki Kaisha Light source device and illumination apparatus

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110141050A1 (en) 2008-09-03 2011-06-16 Nariaki Miura Gesture input operation device, method, program, and portable device
TW201237389A (en) * 2011-03-15 2012-09-16 Lextar Electronics Corp Die inspection machine with multi-wave domain searching light source

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4363997A (en) * 1979-09-21 1982-12-14 Hitachi, Ltd. Fluorescent lamp having reflective layer
US4393330A (en) * 1980-10-20 1983-07-12 North American Philips Electric Corp. Method for effectively contacting manganese-activated zinc silicate phosphor with antimony oxide during phosphor coating, and resulting lamp
US4447756A (en) * 1980-04-08 1984-05-08 Tokyo Shibaura Denki Kabushiki Kaisha Fluorescent lamp with layer of plural phosphors having different particle sizes
US4623816A (en) * 1985-04-22 1986-11-18 General Electric Company Fluorescent lamp using multi-layer phosphor coating
US4847533A (en) * 1986-02-05 1989-07-11 General Electric Company Low pressure mercury discharge fluorescent lamp utilizing multilayer phosphor combination for white color illumination
US4940918A (en) * 1989-07-24 1990-07-10 Gte Products Corporation Fluorescent lamp for liquid crystal backlighting
US5402036A (en) * 1991-01-30 1995-03-28 Toshiba Lighting And Technology Corporation Low pressure mercury vapor discharge lamp having double layers
US5854533A (en) * 1992-10-19 1998-12-29 Gte Products Corporation Fluorescent lamps with high color-rendering and high brightness
US5944572A (en) * 1996-05-13 1999-08-31 General Electric Company Fluorescent lamp with phosphor coating of multiple layers
US20030011310A1 (en) * 2001-06-20 2003-01-16 Thomas Juestel Low-pressure gas discharge lamp with phosphor coating
US20060113885A1 (en) * 2004-11-29 2006-06-01 Keiji Iimura Discharge fluorescen apparatus including fluorescent fibers
US20060170325A1 (en) * 2005-01-28 2006-08-03 Kenji Okishiro Liquid crystal display device
US20070121032A1 (en) * 2005-11-28 2007-05-31 Hitachi Displays, Ltd. Liquid crystal display device

Patent Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4363997A (en) * 1979-09-21 1982-12-14 Hitachi, Ltd. Fluorescent lamp having reflective layer
US4447756A (en) * 1980-04-08 1984-05-08 Tokyo Shibaura Denki Kabushiki Kaisha Fluorescent lamp with layer of plural phosphors having different particle sizes
US4393330A (en) * 1980-10-20 1983-07-12 North American Philips Electric Corp. Method for effectively contacting manganese-activated zinc silicate phosphor with antimony oxide during phosphor coating, and resulting lamp
US4623816A (en) * 1985-04-22 1986-11-18 General Electric Company Fluorescent lamp using multi-layer phosphor coating
US4847533A (en) * 1986-02-05 1989-07-11 General Electric Company Low pressure mercury discharge fluorescent lamp utilizing multilayer phosphor combination for white color illumination
US4940918A (en) * 1989-07-24 1990-07-10 Gte Products Corporation Fluorescent lamp for liquid crystal backlighting
US5402036A (en) * 1991-01-30 1995-03-28 Toshiba Lighting And Technology Corporation Low pressure mercury vapor discharge lamp having double layers
US5854533A (en) * 1992-10-19 1998-12-29 Gte Products Corporation Fluorescent lamps with high color-rendering and high brightness
US5944572A (en) * 1996-05-13 1999-08-31 General Electric Company Fluorescent lamp with phosphor coating of multiple layers
US20030011310A1 (en) * 2001-06-20 2003-01-16 Thomas Juestel Low-pressure gas discharge lamp with phosphor coating
US20060113885A1 (en) * 2004-11-29 2006-06-01 Keiji Iimura Discharge fluorescen apparatus including fluorescent fibers
US20060170325A1 (en) * 2005-01-28 2006-08-03 Kenji Okishiro Liquid crystal display device
US20070121032A1 (en) * 2005-11-28 2007-05-31 Hitachi Displays, Ltd. Liquid crystal display device
US7466375B2 (en) * 2005-11-28 2008-12-16 Hitachi Displays, Ltd. Liquid crystal display device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9494284B2 (en) 2014-03-05 2016-11-15 Sharp Kabushiki Kaisha Light source device and illumination apparatus
US10190733B2 (en) 2014-03-05 2019-01-29 Sharp Kabushiki Kaisha Light source device and illumination apparatus

Also Published As

Publication number Publication date
CN101261920A (zh) 2008-09-10
JP2008226492A (ja) 2008-09-25

Similar Documents

Publication Publication Date Title
JP4310243B2 (ja) 液晶表示装置
JP4363467B2 (ja) 蛍光体とこれを用いた蛍光ランプ、並びに、蛍光ランプを用いた表示装置及び照明装置
KR100839945B1 (ko) 백색 광원이 있는 백 라이트 시스템이 제공되는 액정 화상 스크린, 백 라이트 시스템 및 백색 광원
TWI223830B (en) Fluorescent lamp and liquid crystal display device having the same
CN101261386A (zh) 液晶显示装置及发光单元
US20080218664A1 (en) Fluorescent lamp and imaging device usign the same
KR101450785B1 (ko) 표시장치용 형광램프, 이를 갖는 백라이트 어셈블리 및이를 갖는 표시장치
US7940354B2 (en) Liquid crystal display device
JP4892230B2 (ja) 液晶表示装置
US20060001353A1 (en) Flat fluorescent lamp
JP2009161731A (ja) 蛍光ランプ用蛍光混合物、表示装置用蛍光ランプ、これを有するバックライトアセンブリ及び表示装置
KR20070077454A (ko) 형광 램프 및 조명 장치
JP2009123406A (ja) 外部電極型希ガス蛍光ランプ
JP4927352B2 (ja) 画像表示装置
JP2009295541A (ja) 蛍光ランプおよび液晶表示装置
US8310141B2 (en) Fluorescent lamp, light source apparatus and display apparatus
JP2009102502A (ja) 蛍光ランプ及びそれを用いた液晶表示装置
WO2006051979A1 (ja) 蛍光ランプ
JP3601775B2 (ja) バックライト装置、及び液晶表示装置
DE DK et al. FLÜSSIGKRISTALLBILDSHIR MIT WEISSLICHTQUELLE ECRAN CINEMATOGRAPHIQUE A CRISTAUX LIQUIDES AVEC SOURCE DE LUMIERE BLANCHE
KR20100116967A (ko) 액정표시장치모듈
JP2009009704A (ja) 蛍光ランプ及びそれを用いた液晶表示装置

Legal Events

Date Code Title Description
AS Assignment

Owner name: HITACHI DISPLAYS, LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:IMAMURA, SHIN;OKISHIRO, KENJI;NISHIKAWA, MASAKI;REEL/FRAME:020614/0490;SIGNING DATES FROM 20071220 TO 20071226

Owner name: HITACHI DISPLAY DEVICES, LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:IMAMURA, SHIN;OKISHIRO, KENJI;NISHIKAWA, MASAKI;REEL/FRAME:020614/0490;SIGNING DATES FROM 20071220 TO 20071226

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION